According to the agency, “because original OxyContin provides the same therapeutic benefits as reformulated OxyContin, but poses an increased potential for certain types of abuse, the FDA has determined that the benefits of original OxyContin no longer outweigh its risks and that original OxyContin was withdrawn from sale for reasons of safety or effectiveness.”

OxyContin’s manufacturer, Purdue Pharma, reformulated the drug in 2010 to make it more difficult to crush, break, or dissolve; the reformulated pill forms a viscous hydrogel and cannot be easily prepared for injection. The FDA noted Tuesday that abuse of OxyContin by these routes, as well as the oral route, is still possible.

The FDA’s decision came on the same day that Purdue’s patent on the original OxyContin expired, which normally opens the door for generic drug makers to launch their own cheaper versions of a product. Now, these generic companies will have to develop their own abuse-deterrent designs, preserving Purdue’s monopoly on the OxyContin market for the time being.

Critics have raised concerns that the FDA’s decision to bar generic OxyContin may push patients towards less effective drugs without eliminating the risk of addiction, or that generic companies may rush to create abuse-deterrent versions and falsely market to prescribers that these pills are less addictive.